1. Field of the Invention
The present invention relates generally to methods and apparatus for attenuating and/or baffling transient pressure waves in relatively incompressible materials in organs of the body, including, but not limited to the following systems of the human body: cardiovascular, pulmonary, renal/urological, gastrointestinal, hepatic/biliary, gynecological, central nervous, musculoskeletal, otorhinolaryngical and ophthalmic.
In one particular aspect, the present invention relates generally to the field of urology and gynecology, and in particular to the treatment of disorders of the urinary tract caused by sudden fluctuations of intravesical pressure. More specifically, in this aspect of the present invention, methods and devices are provided for the diagnosis and treatment of urinary disorders such as incontinence, urgency, frequency, interstitial cystitis, irritable bladder syndrome and neurogenic bladders.
2. Description of the Related Art
Pressure waves are known to propagate through incompressible fluids in various organs of the body. These pressure waves may be caused by a number of events including events within the body, such as a beating heart, breathing in the lungs, peristalsis actions in the GI tract, movement of the muscles of the body, or events such as coughing, laughing, external trauma to the body, and movement of the body relative to gravity. As the elasticity of the surrounding tissues and organs, sometimes referred to as compliance, decreases, the propagation of these pressure waves increases. These pressure waves have many undesirable effects ranging from discomfort, to stress on the organs and tissue, to fluid leakage such as urinary incontinence, to renal failure, stroke, heart attack and blindness.
Pressure accumulators and wave diffusers are types of devices that can modulate pressure waves in various nonanalogous settings. Accumulator technology is well known and used in hydraulic systems in aircraft, manufacturing equipment, and water supply and distribution since the 1940s. Common types of accumulators include bladder accumulators, piston accumulators, non-separator (air over fluid), and weight loaded type accumulators.
Wave diffusers also affect the transmission of pressure waves in incompressible systems in various settings. The function of such diffusers is to interrupt the progress of a pressure wave and distribute the energy of the wave in so many directions so as to destroy the integrity of a uniform wavefront and its resultant effects. Wave diffusers may be used to protect a specified area from the impact of a wavefront.
Urinary tract disorders are a widespread problem in the United States and throughout the world, affecting people of all ages both physiologically and psychologically. Urinary tract disorders have a number of causes including birth defects, disease, injury, aging, and urinary tract infection.
In light of the foregoing, a number of attempts have been made to combat these disorders. One such attempt involves the use of an indwelling catheter connected to a collection bag with a clamping device on the catheter. Indwelling catheters, however, have a number of drawbacks. For instance, there is an infection risk associated with indwelling catheters, which provide a direct passage for bacteria or other microorganisms into the bladder. Thus, indwelling catheters can only be used for relatively short-term situations. In addition, indwelling catheters and associated collection bags are not cosmetically appealing to most patients.
An attempt at solving urinary incontinence involves the use of prosthetic urethral valves. One such prior art valve utilizes an inflatable cuff that is inserted around the outside of the urethra. The urethral valves of the prior art also have numerous disadvantages. One disadvantage of these valves is that they typically require surgery for installation, and some prior art valves must be operated externally and are therefore dependent on manual intervention.
The use of intra-urethral valves is also known. Typical intra-urethral valves of the prior art also generally require manual intervention. Another problem associated with prior art intra-urethral valves is that the valves may be displaced into the bladder or expelled from the urethra. There is also an infection risk associated with many such valves since they often extend into the meatus and/or have portions of the device external to the urethra providing a passage for microorganisms into the bladder.
Electrical stimulation therapy including rectal, intra-vaginal and external has been attempted to tone the muscles and stimulate nerves supporting the bladder and urethra. This therapy requires lengthy and numerous treatments, and any benefits derived from the therapy typically diminish when the treatments are stopped.
Current surgical incontinence procedures typically focus on the augmentation of urethral flow resistance. Prior art surgical interventions include bladder neck suspensions and bulk (collagen) injections. Although these procedures can be clinically effective with certain patients, problems include widely variable clinical outcomes, relative high costs to perform, potential complications related to surgery, and any effects may be short lived.
Drug therapy exists for a number of urinary tract conditions, including overactive bladder. These drugs include oral medications (systemic) and drugs delivered directly into the bladder. These drugs typically suffer from side effects, lack of effectiveness and high morbidity. Oral medications typically do not allow immediate relief of symptoms and includes side effects such as dry mouth and constipation. Drugs delivered directly into the bladder often require continuous or intermittent catheterization for introduction of the therapeutic agents at the clinically appropriate time.
The intent of the treatment methods described to date either focus on the augmentation of urethral flow resistance, the temporary stoppage or absorption of all urethral flow, or relxing the detrusor muscles to minimize unwanted contractions. The disadvantages and limitations of the prior art treatments are numerous and include:    an excessively high level of patient interaction is typically required to operate and/or maintain the devices, especially for elderly patients and for physically or mentally challenged patients;    limited clinical efficacy;    restricted urine outflow;    patient discomfort and side effects;    urethral and bladder infections related to the devices used; and    relatively expensive when compared to non-clinical solutions (diapers, pads, etc.).
These prior art approaches do not address the reduction in dynamic compliance which results in increased intravesical bladder pressure.